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June 26, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Zn + 2HCl = ZnCl2 + H2 Which amount would produce more H2: 17gramsZn OR 150 mL of 0.5HCl?
Monday, December 7, 2015 by Ashley

CHEMISTRY
A quantity of N2 occupies a volume of 1.5 L at 300 K and 1.2 atm . The gas expands to a volume of 3.2 L as the result of a change in both temperature and pressure.
Monday, December 7, 2015 by Anonymous

Chemistry-Dr.Bob
What is the increasing dipole moment for CO,CS, and SiS? My answer: SiS<CO<CS Is this correct?
Monday, December 7, 2015 by Sanaya

chemistry
how many electrons are transfered in one atom of Mn in the reaction?MnO2+4HCl=MnCl2+2H2O+Cl2
Monday, December 7, 2015 by Natty

chemistry
A sample consist only NaCl and NaBr has amass of 0.7648gm. This sample is place in solution in which excess of silver is added which forma precipitate the AgCl and AgBr has amass of 1.5758 gm . what's the percentage of Cl and Br in original sample ?
Monday, December 7, 2015 by Nechirwan

Chemistry
How can you tell if a compound is polar or nonpolar? Is it just by lewis structures? what would copper (II) phosphate be?
Monday, December 7, 2015 by Sarah

chemistry
ΔH°rxn is -114.14 kJ/mol. Calculate ΔH°f of gaseous nitrogen monoxide, given that ΔH°f of NO2(g) is 33.90 kJ/mol.
Monday, December 7, 2015 by lee

Chemistry
When given different elements and asked for the highest boiling point, do you figure out the molar mass and pick the highest one as the highest boiling point?
Monday, December 7, 2015 by Sarah

Chemistry
A pot containing 500 g of water at 100 degrees Celsius would require how much energy to boil off completely
Monday, December 7, 2015 by Erika

chemistry
Calculate the molarity of a 6% solution of ammoniun nitrate of density 1.025 g/mL
Monday, December 7, 2015 by derek

Chemistry
Sodium chloride dissolves in water (solubility in water is 361g/1L), but copper (II) phosphate does not dissolve in water (insoluble). A. Describe in a stepwise fashion how the solid sodium chloride dissolves in the water to form a solution. (name the resulting interparticle ...
Sunday, December 6, 2015 by Anonymous

chemistry
a gas has a volume of 95 mL at a pressure of 930 torr. What volume will the gas occupy if the pressure is increased to 970 torr and the temperature remains constant
Sunday, December 6, 2015 by viridiana

Chemistry
34.09 ml of 0.251 M KOH is required to tritate a 10.2951 g sample of acetic acid solution. The density of the solution had been previously found to be 1.007g/ml. what is the molarity of the aetic acid solution?.
Sunday, December 6, 2015 by sandra

Chemistry
Can pi bonds be made from d-orbitals?
Sunday, December 6, 2015 by Sanaya

chemistry
How to solve this problem in counting atoms 2 pb(CN)2
Sunday, December 6, 2015 by bob

Chemistry
How many grams of cesium chloride (CsCl) will be needed to make 750. mL of a 0.100 M CsCl aqueous solution? The formula mass of CsCl is 168.36 g/mol. Remember Molarity: M = (mol solute) / (L of solution) I need help solving this problem
Sunday, December 6, 2015 by Mark

Chemistry
A compound that you are studying is soluble in CCl4 but not in water. Would you predict that the compound is polar or nonpolar? Why? [Please explain; don’t just give a trivial answer such as “Because like dissolves like”.]
Sunday, December 6, 2015 by Mark

Chemistry
150 g of water at 80 degree Celsius is cooled to 50 degree Celsius how much heat is lost bye the water
Sunday, December 6, 2015 by Kelly

Chemistry
Chart: Group, Bond length, Bond strength, H-X-H Bond Angle NH3: 1.000, 391, 107 PH3: 1.412, 322, 93.5 AsH3: 1.510, 247, 92 SbH3: 1.688, 247, 92 What physical states do these molecules exist at room temperature? Gas Briefly explain the observed trend in bond length. Briefly ...
Sunday, December 6, 2015 by Anonymous

Chemistry (Check)
Which of the following exhibits the highest boiling point? a. Ne, Ar, Kr, or Xe? Xe b. HF, HCl, HBr, or HI? HI c. CH3CH3, CH3COOH, or CH3OCH3? CH3COOH d. F2, Cl2, Br2, or I2? I2 e. NaCl, SO2, or N2? SO2 Are these right? I just went by molar mass. If these are wrong, please ...
Sunday, December 6, 2015 by Anonymous

chemistry
Consider the following equation: CO + 2 H2 → CH3OH △H rxn = -128 kJ Calculate the amount of heat (in kJ) associated with complete reaction of 8.08 g H2
Sunday, December 6, 2015 by katia

chemistry
Consider the following reaction: 2 Mg + O2 → 2 MgO △H rxn = -1203 kJ Calculate the amount of heat (in kJ) associated with complete reaction of 4 moles of Mg.
Sunday, December 6, 2015 by katia

Chemistry (Check and Help)
Hey can you please check my answers? Also, Can you explain interparticle force of attraction? I'm not sure about the difference between IMFOA and IPFOA. Chemical formula: Cl2 Name: Chlorine Bond Type (intermolecular FOA): London VSEPR molecular shape: tetrahedral Central ...
Sunday, December 6, 2015 by Anonymous

chemistry
Help me solve it. Step by step please The value of kp at 20°c for the reaction 2NO(g) +Cl2(g) 2NOCl(g) is 1.9x10^3 atm-1 calculate the value of KC at the same temperature.
Sunday, December 6, 2015 by john

chemistry
how many joules are needed to completely melt 25 grams of ice at 0 degree celcius?
Sunday, December 6, 2015 by b

chemistry
0.5g of an organic compound x (containing carbon hydrogen oxygen) produces 0.733g of carbondioxide and 0.3g of water on complete combustion.the max spectrum shows mr=60.determine molecular formula of x
Sunday, December 6, 2015 by ali

chemistry
What is the enthaphly change when 2 moles of fe(111)oxide is reduced by 3 moles of aluminium ♢Hf Al2O3= -1676kJ mol-1 ♢Hf (Fe2O3)= -825kJmol-1
Sunday, December 6, 2015 by yap97

chemistry
A pound of coffee beans yields 56 cups of coffee (4 cups= 1 qt.) how many milliliters of coffee can be derived from 2.2g of coffee beans?
Sunday, December 6, 2015 by tagiz

Chemistry
In a moist room (44m3) 4 kg dry CaCl2 is placed. The room contains 10 g/m3 of H20. How much of the CaCl2 is converted to CaCl2*2H2O? Temperature 10 deg C. Equilibrium constant is 10^5 atm-2 at 10 deg C. I've caclulated Kp to 0,0032 atm and then tried to convert to Kc to 1,...
Sunday, December 6, 2015 by Henrik

Chemistry
How many grams of 10% wt BaCl2 solution will be necessary to produce 5.6g BaCl2?
Sunday, December 6, 2015 by ange

Chemistry
Name the compound or give molecular formula. 1. Pt(NO2)2 : ? Is it Platinum (II) Nitrite 2. Manganese (II) bromide pentahydrate:? Is it MnBr2 • 5H2O
Sunday, December 6, 2015 by Sanaya

Chemistry
Calculate the frequency of light associated with the emission from n=5 to n=4 in the hydrogen atom. I got -7.41 x10^13 Hz, but the answer would make sense if it is positive... So does this mean that when the electrons jump from n=5 to n=4, energy is emitted, but the energy has...
Sunday, December 6, 2015 by Sanaya

Chemistry
Can pi bonds be made from d-orbitals?
Sunday, December 6, 2015 by Sanaya

Chemistry
Let us assume that Cu(OH)2(s) is completely insoluble, which signifies that the precipitation reaction with NaOH(aq) (presented in the transition) would go to completion. If you had a 0.300 L solution containing 0.0230 M of Cu2+(aq), and you wished to add enough 1.31 M NaOH(aq...
Sunday, December 6, 2015 by Anonymous

Chemistry
the effective incoming solar radiation per unit area on earth is 342 W/M^2. of this radiation, 6.7 W/m^2 is absorbed by CO2 at 14993 nm in the atmosphere. how many photons at this wavelength are absorbed per second in 1 m^2 by CO2?
Saturday, December 5, 2015 by Anonymous

Chemistry
1) Balance the following equation in basic conditions: 2CoCl2 + Na2O2 --> 2Co(OH)3 + 4Cl^- + 2Na^+ 2) Balance the following equation in acidic conditions: H3AsO3 + I2 --> H3AsO4 +2I^-
Saturday, December 5, 2015 by Green

Chemistry
An excited ozone molecule, O3*, in the atmosphere can undergo one of the following reactions, O3* → O3 (1) fluorescence O3* → O + O2 (2) decomposition O3* + M → O3 + M (3)deactivation, where M is an inert molecule, the rate constant for the fluorescence ...
Saturday, December 5, 2015 by Anonymous

Chemistry (Gas)
A cylinder is filled with 120L of air at 101 kPa and 20*C. How long could the cylinder be used "just underwater" on earth assuming 2L is used every 5 seconds. I don't understand what the pressure and temperature would be "just underwater." Is it assumed...
Saturday, December 5, 2015 by A

chemistry
Stoichiometrics: a 36 grams sample of calcium hydroxide is allowed to react with 40.5 grams of phosphoric acid according to the following reaction. 3Ca(OH)2 + 2H3PO4 = Ca3(PO4)2 + 6H2O how many grams of calcium phosphate are produced? how many moles of Calcium phosphate are ...
Saturday, December 5, 2015 by kevin

chemistry
Devils food cake has a [H+] of 2.7 x 10-8 mol/L. calculate pH pOH [OH-]
Saturday, December 5, 2015 by emilio

chemistry
a 36 grams sample of calcium hydroxide is allowed to react with 40.5 grams of phosphoric acid according to the following reaction. how many grams of calcium phosphate are produced? how many moles of calcium phosphate are produced? how many moles of excess reagent remain? if 43...
Saturday, December 5, 2015 by kevin

Chemistry
At the start of a road trip, the pressure of the air in a car tire is 276kPa and the temperature is 12.0 degrees Celsius. After driving for some time the pressure in the tire is now 303kPa. Assuming that the volume of the air inside the tire remains constant, determine the new...
Saturday, December 5, 2015 by Joseph

chemistry
a 36 grams sample of calcium hydroxide is allowed to react with 40.5 grams of phosphoric acid according to the following reaction.
Saturday, December 5, 2015 by kevin

Chemistry
. A typical polyethylene bag from a grocery store weighs 12.4 g. How many molecules of ethylene, C2H4, must be polymerized to make such a bag?
Saturday, December 5, 2015 by Anonymous

chemistry
Which law of chemical combination is illustrated by the fact that 168g fe reacts with 72g H2O to from 232g Fe3 O4 and 8gH2?
Saturday, December 5, 2015 by farheen fathima

chemistry
How would your calculated %P2O5 value be affected if you had not used this blank solution
Friday, December 4, 2015 by sami

Chemistry
An unknown mass of caco3 was added to an excess of 2mol/dm3 hcl. Calculate the total volume of co2 evolved.
Friday, December 4, 2015 by Tan

Chemistry
Calculate the final temperature in degrees Fahrenheit of 1.25 liters of gas X at 85 degrees Celsius and 2700 mm/Hg, if the pressure is changed to 2.35 atmospheres and the volume is increased to 2500ml
Friday, December 4, 2015 by Kevin

Chemistry
if 16.5 liters of gas X is at 398 torr and -90.5 degrees celsius, what would be the volume of this same gas if the pressure is changed to 3.1 atmospheres and the temperature is changed to 399K
Friday, December 4, 2015 by Kevin

chemistry
Which law of chemical combination is illustrated by the fact that 168g fe reacts with 72g H2O to from 232g Fe3 O4 and 8gH2?
Friday, December 4, 2015 by farheen fathima

Chemistry
How many grams of cesium chloride (CsCl) will be needed to make 750. mL of a 0.100 M CsCl aqueous solution? The formula mass of CsCl is 168.36 g/mol Molarity: M = (mol solute) / (L of solution)
Friday, December 4, 2015 by Mark

Chemistry
The highest temperature ever recorded in Palm Desert, California, was 122„aF. Express this temperature in degrees Kelvin.
Friday, December 4, 2015 by John

chemistry 101
The value of kp at 20°c for the reaction 2NO(g) + Cl2(g) 2NOCl(g) is 1.9x10^3 atm-1 calculate the value of KC at the same temperature.
Friday, December 4, 2015 by Sidney

chemistry
what is the molar solubility of Fe(OH)3 in a buffered solution with pH=8.2 at 25 degrees Celsius given ksp =4.0*10^-38.
Friday, December 4, 2015 by cliff

Chemistry
in a particular redox reaction, Cr is oxidized to CrO42- and Ag+ is reduced to Ag. Complete and balance the equation for this reaction in acidic solution.
Friday, December 4, 2015 by Anonymous

statistics
a student gets the following grades in his 5 subjects: 87 for calculu; 82 for Physics; 79 for Chemistry; 81 for english; 83 for history. Compute the weighted mean if the weights for the 5 subjects are 5,4,4,3, and 3, repectively
Friday, December 4, 2015 by wew

chemistry
how many grams of the solid can be formed from 206g of calcium nitrate and 140 g of phosphoric acid? answer in grams. I really need help and fast.
Thursday, December 3, 2015 by Grace

Chemistry
1) Balance the following equation in basic conditions: 2CoCl2 + Na2O2 --> 2Co(OH)3 + 4Cl^- + 2Na^+ 2) Balance the following equation in acidic conditions: H3AsO3 + I2 --> H3AsO4 +2I^-
Thursday, December 3, 2015 by Green

Honors Chemistry
Predict Products and write balanced equation FeBr3 + 3Ba(0H)2
Thursday, December 3, 2015 by Jon

Chemistry
a sample of a compound with a mass of 0.4168g is extracted from a plant. Decompostion of this sample produces 0.1667g of carbon, 0.2223g oxygen, and the remainder is hydrogen. What is the percentage compostion (by mass) of the compound?
Thursday, December 3, 2015 by Cali

organic chemistry
Because alcohol protons are reasonably acidic and easily undergo exchange, it is important that the base be matched to the appropriate solvent. Explain why it would be virtually impossible to sort out the factors the size of the base or the stability of the alkenes formed if a...
Thursday, December 3, 2015 by jacob

organic chemistry
A methyl ether (SN2 product) can form as a byproduct in the sodium methoxide reaction. What is its structure? Provide the mechanism for the formation of the methyl ether product, in addition to answering the question.
Thursday, December 3, 2015 by caili

Chemistry
A mixture of H2 and water vapor is present in a closed vessel at 20°C. The total pressure of the system is 755.0 mmHg. Partial pressure of water vapor at 20°C equals 17.5 mmHg. What is the partial pressure of H2?
Thursday, December 3, 2015 by Katlen

Chemistry
Ammonium carbonate decomposes upon heating according to the balanced equation: (NH4)2CO3(s) -> 2NH3(g)+CO2(g)+H2O(g) Calculate the total volume of gas produced at 27.0 degrees C and 2.03 atm from the reaction of 1.4kg of (NH4)2CO3. What is the pressure of each of the gases ...
Thursday, December 3, 2015 by Stephanie

Chemistry
What is the maximum mass of copper(ii) sulphate pentahydrate, CuSO4.5H2O, which could be obtained by crystallizing the solution? Ar: H=1; O=16; S=32; Cu=63.5 I'm not looking for someone to do it all, although that would help. Just that someone could give me guidance and ...
Thursday, December 3, 2015 by Owen

Chemistry
How do i prepare 17% HNO3 from 69%-70.5% HNO3 of 1.42g/ml density
Thursday, December 3, 2015 by Zhuky

Chemistry
In a certain process a block of lead with a mass of 150g undergoes a temperature drop of 55.0 Celsius. In the process of 1072 J of heat energy is released from the Lead. What is the specific heat of Lead.
Thursday, December 3, 2015 by Chico

Chemistry
Calculate the pH of a 0.18 M solution of cyanide ion, CN- given the Ka (HCN) = 6.2 x 10^-10. I know how to calculate Ka and Kb values no problem, but I don't know which value to use in my calculations. Is it based on the conjugate base/acid formed or hydronium or hydroxide...
Wednesday, December 2, 2015 by Tim

Chemistry
How many minutes does it take to form 10L of O2 measured at 92.2 kPa and 28°c from water if a current of 1.3 A passes through the electolytic cell? a) how many minutes? b)What mass in grams of h2 forms?
Wednesday, December 2, 2015 by Peggy

chemistry
a saturated NH4Cl aqueous solution is prepared in 100g oh water t 25 celsius. how much solute is in solution.
Wednesday, December 2, 2015 by Mia

Chemistry
How do you determine the number of valence electrons in one atom of each of the following elements. ... We had 20 elements overall for homework so I listed the first 5 A) Na B.) F C.) Rb D.) Ba E.) I
Wednesday, December 2, 2015 by Allison

chemistry
​An empty glass container has a mass of 418.634 grams. It has a mass of 419.514 grams after it has been filled with nitrogen gas at a pressure of 790 mmHg and a temperature of 15oC. When the container is evacuated and refilled with a certain element X at a pressure of ...
Wednesday, December 2, 2015 by Noora

chemistry
You have 310. mL of a 5.75×10-5 M Pb(NO3)2 solution. How many moles of NaCl must be added to precipitate a solid? The Ksp of PbCl2 is 1.6×10-5. I'm not sure where to go after I make the ICE table
Wednesday, December 2, 2015 by matt

AP Chemistry
The reaction of 5.1 grams of fluorine with excess chlorine produced 4.5 grams of ClF3. What percent yield of ClF3 was obtained? Answer in unites of %
Wednesday, December 2, 2015 by Zach

Chemistry
C7H6O3 + C4H6O3 → C9H8O4 + C2H4O2 If you start with 2.09 grams of C4H6O3 how many grams aspirin (C9H8O4) can you make?
Wednesday, December 2, 2015 by Mark

Organic Chemistry
A methyl ether (SN2 product) can form as a byproduct in the sodium methoxide reaction. What is its structure? Provide the mechanism for the formation of the methyl ether product, in addition to answering the question.
Wednesday, December 2, 2015 by caili

Organic Chemistry
Because alcohol protons are reasonably acidic and easily undergo exchange, it is important that the base be matched to the appropriate solvent. Explain why it would be virtually impossible to sort out the factors the size of the base or the stability of the alkenes formed if a...
Wednesday, December 2, 2015 by brooklyn

chemistry
How many minutes does it take to form 10L of O2 measured at 92.2 kPa and 28°c from water if a current of 1.3 A passes through the electolytic cell? a) how many minutes? b)What mass in grams of h2 forms?
Wednesday, December 2, 2015 by Peggy

Chemistry
112.00g of nitrogen gas is reacted with an excess or abundant amount of oxygen gas. The single product, a gas, is determined to have a mass of 431.92 g. Additional experiments showed that the product consisted of 2.0 moles. a) how many grams of oxygen reacted? b) what percent ...
Wednesday, December 2, 2015 by Maria

Chemistry
0.400 g of a solid base X(OH)2 was dissolved in 50.0 mL of water. The solution was neutralized with 65.80 mL of 0.150 mol/L HCl. Calculate the molar mass of the base. Do I need to set up a dilution equation? I'm not sure what to do.
Wednesday, December 2, 2015 by Anon

Chemistry
A 38.5 mL sample of HBr is titrated with 112 mL of 1.05 mol/L KOH. The density of the HBr solution is 1.75 g/mL. Calculate the percentage by mass of the HBr in the sample. How come we don't use density*volume to find the moles of HBr?
Wednesday, December 2, 2015 by Sam

Chemistry
Adding 1.00 g of benzene, C6H6, to 80 g of cyclohexane, C6H12, lowers the freezing point of the cyclohexane from 6.5 to 3.3 degree celsius. What is the value of kf for cyclohexane?
Wednesday, December 2, 2015 by Robin

Chemistry
I'm supposed to estimate the ΔH for O || H2C=CH2 +O3(g)--- CH3CH(g) + O2(g) and i got [4(432)+(614)+(1072)]-[3(413)+(347)+(745​)+(358)+(467)] the answer i got was 182 but the answer was wrong and i'm not sure what i did wrong.
Tuesday, December 1, 2015 by Jacqueline

chemistry
Determine the specific heat of a material if a 28.4 g sample absorbed 42.9 J as it was heated from 293 K to 336 K. Units are J/g · K.
Tuesday, December 1, 2015 by bee

Chemistry
Assume earth travels in UCM in orbit around the sun R=1.50 x 10 to the 11th power m T-365.25
Tuesday, December 1, 2015 by Anonymous

Physical Chemistry
If the n = 3 to n = 4 transition for a certain particle-in-a-box system occurs at 4.00 x 10^13 s -1 , find the frequency of the n =6 to n =9 transition in this system.
Tuesday, December 1, 2015 by Lorin

Chemistry
30.0 mL of 0.0200 mol/L NaOH are added to 70.0 mL of 0.0100 mol/L HCI. Calculate the [H3O+] and [OH─] of the resulting solution My answer: [OH-] = 1.00x10^-10 M; [H3O+] = 1.00x10^-4 M Teacher's answer: [OH-] = 1.00x10^-11 M; [H3O+] = 1.00x10^-3 M Am I missing ...
Tuesday, December 1, 2015 by Sam

chemistry
Approximately how many joules of heat are needed to raise the temperature of a 4.0-gram sample of water to 8.0C? that is all of the information that was provided
Tuesday, December 1, 2015 by Caroline

Chemistry
In which of the following substances does sharing of electrons between two atoms occur? He Nal PO43– Ag
Tuesday, December 1, 2015 by Sara

Chemistry
Which of the following elements is least likely to form a cation that will then form an ionic bond with an ion of a Group 7A element? S K Rb Fr
Tuesday, December 1, 2015 by Sara

oscotech
chemistry: is the formula to be used @ 25 degree c is E=Eo -(0.059/n(log a)) or Eo+(0.059/n)(log a)
Tuesday, December 1, 2015 by olagunju

Chemistry
Which of the following is a bond in which a metal transfers one or more electrons to a nonmetal? ionic bond hydrogen bond metallic bond covalent bond
Tuesday, December 1, 2015 by Sara

Chemistry
A 0.600 m aqueous solution of KBr has a total mass of 69.0 g. What masses of solute and solvent are present?
Tuesday, December 1, 2015 by Troy

chemistry
make 100ml of 0.50mol/L CuSO4 by diluting part of the 0.100 mol/L
Tuesday, December 1, 2015 by Anonymous

Organic Chemistry
Which is more polar trans-methyl cinnamate or trans-chalcone?
Tuesday, December 1, 2015 by Bianca

Chemistry
If you place 1.26 g of solid silicon in a 6.54 L flask that contains CH3Cl with a pressure of 634 mm Hg at 25°C, what mass of dimethyldichlorosilane, (CH3)2SiCl2(g), can be formed?
Tuesday, December 1, 2015 by Julian

Chemistry
The ionization energies (kJ/mol) of hydrogen (H), nitrogen (N), sodium (Na), and oxygen (O) are 1,312, 1,402, 1,681, and 1,314, respectively. Which element combination is least likely? OH– NO3– NH4+ NaO–
Tuesday, December 1, 2015 by Sara

Chemistry
Which of the following is a monatomic cation? Br NH4+ SO42– Fr+
Tuesday, December 1, 2015 by Sara

Chemistry
The population ratio between two energy levels separated by 1.4 ✕ 10−22 J is 0.69. What is the temperature of the system?
Tuesday, December 1, 2015 by Anonymous

Chemistry
Which of the following elements is most likely to form an ion that will then form an ionic bond with an ion of a Group 1A element? Pt I Fr Be
Tuesday, December 1, 2015 by Sara

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